Bingo!! No, I mean Air Gun Fun
Least expensive method I've found is to obtain a childs scribble pad(75-100 sheets) of the uncoated type, a bottle of red Bingo marker and have at it!
Backers on target frames are usually of a paper/wood composit(cheap) and therefore don't hold up well if left out.......try your local building supply for a sheet of 1/2 in.foam insul. board with the foil facing(UV can't get it). Great stuff, the foil also keeps the foam in place, pellets punch clean holes and a sml. roll of Scotch Magic tape will keep your tgt. on and still peel off cleanly.
Need a good use for those empty CO2 cannisters?
This idea came all the way Italy submitted by Roberto. An home-made "spinning target", made using empty co2 capsules. It works fine and it's very cheap. (note the impacts on the capsule, the Eliminator really do his job!)
I found that an old 2 drawer filing cabinet (or new, only $25) works great. Remove the top drawer, hang your target and shoot away. Using the ideas below, the pellets are trapped or stopped and drop down into the lower drawer. The removed drawer also works great as its own target holder/backstop. Just turn it on end (either end, the handle may get in the way) and add one of the pellet traps below.
Rope Caulk- gray putty sold in flat rows in a roll (rows like twizzlers candy). Just cut and lay the bundles flat side by side and stack them up according to your pellet-stopping needs (at least 4 layers deep for 800+ fps). The caulk will stick to anything, so just stick it to a board or in a cheap baking pan (9x11X2 works fine). Then set this in the filing cabinet setup, or use on its own. The caulk sells for about $4 for a 90 yard roll, enough to get 4 layers in a 9x11 pan.
Door Mats- (this is for lower powered pellet guns 800+ pellet guns and higher powered BB guns will blow right through this rig, unless you add layers. Solid rubber or rubber and fiber door mats work great for stopping pellets. (one mat is $7 to 10) Cut it into 4ths (mine produces squares about 10x14). Stack them up and tape around the two long edges and one short edge with duct tape. pellets will get part way through the layers and fall down within the layers. Just turn it over and dump out the spent pellets. You may need to poke some pellets out of the mat. Eventually the mat will crumble, but I get 2000 to 4000 shots before I need to add a layer. You can also prolong the mats life and prevent rubber crumbs mess by adding duct tape layers across the face of the mat rig.